1 /* 2 * Copyright (C) 2010 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef ASYNCHRONOUS_CLOSE_MONITOR_H_included 18 #define ASYNCHRONOUS_CLOSE_MONITOR_H_included 19 20 #include <pthread.h> 21 22 /** 23 * AsynchronousCloseMonitor helps implement Java's asynchronous close semantics. 24 * 25 * AsynchronousCloseMonitor::init must be called before anything else. 26 * 27 * Every blocking I/O operation must be surrounded by an AsynchronousCloseMonitor 28 * instance. For example: 29 * 30 * { 31 * AsynchronousCloseMonitor monitor(fd); 32 * byteCount = ::read(fd, buf, sizeof(buf)); 33 * } 34 * 35 * To interrupt all threads currently blocked on file descriptor 'fd', call signalBlockedThreads: 36 * 37 * AsynchronousCloseMonitor::signalBlockedThreads(fd); 38 * 39 * To test to see if the interruption was due to the signalBlockedThreads call: 40 * 41 * monitor.wasSignaled(); 42 */ 43 class AsynchronousCloseMonitor { 44 public: 45 explicit AsynchronousCloseMonitor(int fd); 46 ~AsynchronousCloseMonitor(); 47 bool wasSignaled() const; 48 49 static void init(); 50 51 static void signalBlockedThreads(int fd); 52 53 private: 54 AsynchronousCloseMonitor* mPrev; 55 AsynchronousCloseMonitor* mNext; 56 pthread_t mThread; 57 int mFd; 58 bool mSignaled; 59 60 // Disallow copy and assignment. 61 AsynchronousCloseMonitor(const AsynchronousCloseMonitor&); 62 void operator=(const AsynchronousCloseMonitor&); 63 }; 64 65 #endif // ASYNCHRONOUS_CLOSE_MONITOR_H_included 66
